<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title></title>
</head>

<body>
  <h2>渲染进程间通信</h2>
  <button id="btn">打开窗口2</button>
  <script src="index.js"></script>
</body>

</html>